Apparatus and method for harvesting plankton and other biomass from a dead zone

ABSTRACT

Apparatus and method for harvesting biomass from a dead zone in a body of water includes structure and/or function whereby, preferably, at least one guide float is configured to float below the water surface. At least one support structure is configured to be coupled to the bottom beneath water, and is configured to support a substantially rigid frame within the dead zone. A main funnel is coupled to (i) the at least one guide float and (ii) the substantially rigid frame within the dead zone, and is configured to collect descending biomass and funnel it toward a lower funnel that is coupled to the bottom of the main funnel. A collection canister is disposed adjacent the lower funnel and is configured to store the descending biomass. Hauling structure is coupled to the guide float and is configured to haul the collection canister from the lower funnel to the surface.

This is a Continuation-In-Part of PCT/US15/61822, filed Nov. 20, 2015(designating the US), which is a continuation of U.S. application Ser.No. 14/551,561, filed Nov. 24, 2014, now U.S. Pat. No. 9,155,248, issuedOct. 13, 2015.

BACKGROUND Technical Field

The present invention relates to system, method and apparatus forharvesting plankton and other biomass, preferably from dead zones inlakes and oceans. Such harvesting of biomass leads to reductions indissolved and atmospheric CO₂ and CH₄, ocean acidity and acid rain.

Overview

A 2008 study (“Spreading Dead Zones and Consequences for MarineEcosystems”, Diaz, Robert J. and Rosenberg, Rutgers, Science 15 Aug.2008: Vol. 321 no. 5891 pp. 926-929, DOI: 10.1126/science.1156401)counted 405 seasonal dead zones encompassing more than 97,000 squaremiles in coastal waters worldwide. By 2014 there were over 550 deadzones. The plankton in these dead zones contain billions of tons ofcarbon. Most plankton are destined to release their carbon as CO₂ and/orCH₄ when they die. The aim of this invention is to interrupt the carboncycle in about half of each dead zone and sequester its carbon. Some canbe sequestered directly, some indirectly by processing the biomass intomethane and fertilizer to replace fossil fuels and chemical fertilizers.See also “A Look Back at the U.S. Department of Energy's Aquatic SpeciesProgram: Biodiesel from Algae: Close-Out Report”, NREL/TP-580-24190,John Sheehan, et al., July 1998. They found that microalgae can “achievevery efficient (>90%) utilization of CO₂”, considerably better thanterrestrial plants.

Harvesting and processing a billion tons of biomass might take a millionqualified boats and 10 million workers. For this to work it should beprofitable: the value of the end products should exceed the cost ofharvesting, processing, transport, etc. Most of the harvesting ispassive, taking advantage of the shortened life cycle of microalgae in adead zone, and using gravity and wave motion to speed the capture. Theenergy required for harvesting is minimal, and the energy for processingand transport need not be from fossil fuel; it can be replaced bymethane (CH₄) produced from the biomass itself. Profits can be used toacquire deforested land and re-plant native trees, fertilized withharvested biomass. These trees will sequester CO₂ for centuries. Thefollowing concepts are helpful to understand and to responsibly use thisinvention.

1. The Aquatic Carbon Cycle.

In a healthy aquatic ecosystem phytoplankton (microalgae) absorbdissolved CO₂ and emit O₂ by photosynthesis. They are the base of thefood chain for aquatic animals and microbes that reverse the carbonexchange by absorbing O₂ and emitting CO₂. A small fraction of thecarbon remains at the bottom, as evidenced by the abundance of coralreefs, carbonate rock, fossil fuels and methane ice.

2. The Diurnal Cycle of Microalgae.

In the photic zone, where there is enough daylight for photosynthesis,microalgae metabolize dissolved CO₂ into glucose and othercarbohydrates. These are heavier than sea water allowing the algae todrift downward to escape predation and to where minerals are moreconcentrated. Like all plants, microalgae need some O₂ at night toprocess nutrients. They get this O₂ from the water and from what theyinternally stored. Leftover carbohydrates are stored as high energylipids (bio-oils). These lipids are lighter than water and allow themicroalgae to drift back up in time for daylight. Blue green algaeproduce an internal gas to allow them to rise. Before reaching thesurface the specific gravity of microalgae is indistinguishable fromthat of the surrounding water. Then the cycle of descent and rise beginsagain.

3. Algal Blooms.

Algal blooms in lakes and oceans are caused by an excess of vitalnutrients, without which microalgae cannot exist. They include salts ofnitrogen, potassium, phosphorous and other trace minerals. Crucial amongthe vital nutrients are CO₂ and, of course, H₂O. Carbohydrates includingglucose and cellulose are made exclusively from C, H and O. Carbonconstitutes 40% of these compounds. Excessive dissolved CO₂ was once sorare that large algal blooms were seldom seen. An excess of nutrientscan come from natural events such as forest fires and floods washingtopsoil into waterways, but more often from man-made sources such as:

-   -   Farming practices. During rainy seasons, eroded soil, soluble        fertilizers, cattle, pig, and poultry farm runoff may reach        rivers and flow into lakes and oceans.    -   Burning fossil fuels. This raises dissolved CO₂ levels in lakes        and oceans. Dissolved CO₂ forms carbonic acid that dissolves        coral reefs, shells, carbonate rock, eggs, etc. The released        calcium is also a vital nutrient for some microalgae.    -   Acidification. Sulfuric acid rain also dissolves minerals. It is        formed as a noxious byproduct from burning coal and making coke        for steel mills.

4. Methane and Methane Ice.

Methane, the main ingredient of natural gas, has the chemical formulaCH₄. If burned with enough O₂ it produces CO₂ and water vapor, bothgreenhouse gases. But unburned methane in the atmosphere is a much morepotent greenhouse gas than CO₂. It is reported that molecule formolecule the CH₄ radiative value is 72 times that of CO₂. Thereforesystemic leakage of methane should be prevented.

In deep water where the pressure is great enough and/or the water iscold enough, methane gets into the crystalline structure of water andforms methane hydrate, otherwise known as methane ice.Pressure-temperature tables for the formation of methane ice areavailable. According to the Lawrence Livermore National Labs, “ . . .the energy locked up in [underwater] methane hydrate deposits is morethan twice the global reserves of all conventional gas, oil, and coaldeposits combined.” Fortunately for life on earth, methane ice isheavier than water.

5. Dead Zones.

In the 1970's large algal blooms started appearing around the mouths ofcertain rivers during warm months. They are called “dead zones” if thedeeper waters have too little dissolved oxygen (hypoxia), or nodissolved oxygen (anoxia). Few living things can survive under theseconditions. In 2002 the dead zone in the Gulf of Mexico alone covered8,500 square miles.

6. Causes of Dead Zones.

Lakes and oceans tend to be stratified by the weight of the water.Highly oxygenated surface water mixes only slightly with the heavier,colder and more saline bottom water. Surface currents range from 0 to5.6 mph, but it barely helps mixing because these speeds reduceexponentially with depth. It is especially true in a dead zone wherethere are neither schools of fish, nor filter feeders to stir things up.As phytoplankton, dead zooplankton, zooplankton excreta and otherbiomass fall to the bottom, aerobic bacteria metabolize it, and in doingso deplete the dissolved O₂. If the region becomes anoxic, MethanogenicArchaeons take over. The domain Archaea, discovered in 1977, containsthe first life forms on earth some 3.6 billion years ago. They cannotfunction in oxygen but thrive in swamps, manure piles and the anaerobiccolons of animals including zooplankton. They emit neither O₂ nor CO₂,but methane (CH₄) and often hydrogen sulfide (H₂S). In water H₂S formshydrosulfuric acid that raises water acidity. In high enoughconcentrations both of these emissions kill plants and animals andspread hypoxia upward.

Algal blooms cloud the water, limiting the depth of the photic zone.Algae have evolved to descend a certain distance during their nightcycle before they drift back upwards. To do this they should have enoughO₂ to produce lipids or gases, without which they continue to sink tothe bottom and worsen hypoxia. Dead zones have very little ecology, butthey have some. For example there are reports of a microbe that canmetabolize CH₄, probably emitting CO₂ and 2H₂O. Whatever these microbesare, they should be thriving in dead zones. Any un-metabolized CH₄ mayevaporate into the atmosphere and accelerate climate change.

7. Uses for Harvested Biomass.

Most chemical fertilizers consist of ammonium nitrate, phosphate andpotash (N—P—K). Over time crops grown with only N—P—K fertilizers leachother needed micro-nutrients out of the soil. The process of makingammonium nitrate consumes 1% to 2% of the world's annual energy supply(see “The Haber Process” at http://en.wikipedia.org/wiki/Haber_process).It is therefore a major contributor to climate change. Phosphates andpotash are mined adding to the energy budget, and phosphates areincreasingly expensive. On the other hand fresh water biomass can beprocessed into fertilizer and CH₄ simply by composting it in ananaerobic digester. Digesters are commercially available and are used incommunities and farms to profit from these products. (Oceanic biomassshould be desalinated before it can be used as fertilizer).

Since aquatic biomass stems from phytoplankton, it contains all thenutrients needed to grow plants. These “marine derived nutrients” orMDNs build topsoil. Researchers at the University of Washington haveshown that Sitka spruce grow over three times faster in watershedsfertilized by migratory salmon (via bears, eagles, otters, and whateverelse eats dying salmon) than in watersheds without salmon. Everythingthat is in the MDN, salmon, had to be also in microalgae, the base ofthe marine food chain. Pyrolysis can be used to sequester carbondirectly, as well as producing methane and other flammable gases. Itinvolves heating biomass in an airtight container. Solar concentratorsare the logical choice of heat source. A film that reflects sunlightwith 95% efficiency has been developed with help from the NationalReusable Energy Laboratories (NREL). Biomass is transformed into char,bio-oil, methane, syngas and ash. The relative amounts of each substancedepend on the temperature of the pyrolysis. The ash contains mineralsthat could be used as fertilizer, if it were desalinated. The char(carbon) can be compressed with a non-flammable binder into blocks andsequestered, perhaps in abandoned coal mines. By comparing the atomicweights of C=12 and CO₂=44 one sees that for every ton of char (C)sequestered, 11/3 tons of CO₂ are kept out of the atmosphere. Thus algaetake dissolved CO₂ out of the water and pyrolysis keeps it out.

8. Where not to Harvest Biomass.

It is well established that plants can produce toxins to combatpredation. Species of dinoflagellates sometimes produce neurotoxins “redtide” that concentrate in shellfish. Some blue-green algae can producetoxins such as microcystin that attacks the liver, and anatoxin-a thatcan kill a person and other animals within five minutes. Fortunatelytests exist for such harmful algal blooms (HABS). Excess CO₂ causes anabundance of microalgae and that causes an abundance of predators andthat may well cause microalgae to produce protective toxins. Thisgrowing problem is yet another reason to lower CO₂ levels. It isdangerous to harvest bottom sediment because disturbing it could releasemethane, hydrogen sulfide, heavy metals, PCBs and other toxins. Itshould not be harvested in waters cold and deep enough to form methaneice because once the biomass is metabolized by methanogens the emittedCH₄ is sequestered as methane ice. This sequesters carbon and reducesCO₂. In these regions the algal bloom tapers off partially from lack ofCO2. It is unwise to harvest near the surface. It makes poor fertilizeras it generally lacks the trace minerals that are more concentrated atgreater depths. Moreover separating such algae from water is difficult.Microalgae near the surface have a specific gravity indistinguishablefrom that of the surrounding water. Therefore it cannot be “spun-dried”in an ordinary centrifuge. A filtering centrifuge would use undueamounts of energy and the filter would quickly clog. Evaporation ispossible but impractical. Algae harvested near the mouth of a pollutedriver may well contain persistent toxins, and should not be used.

9. Some Likely Outcomes.

Millions of people worldwide could be employed for months out of theyear. MDNs could replace chemical fertilizers, un-mined “bio-methane”could become the standard fuel, oceans will be less acidic, atmosphericCO₂ will decrease, dead zones will eventually disappear, and usingprofits for reforestation will restore a more natural climate.

In alternative embodiments to be described below, surface devices andfloats have been replaced with underwater devices, to avoid surfacecongestion and prevent surface collisions.

SUMMARY OF THE INVENTION

An underwater funnel trap is preferably assembled on shore and towed tothe site on pontoons. Arrays of traps connected to one another arepreferably seasonally deployed and removed at the end of the season.This can all be done from boats at the surface. A funnel trap passivelydirects falling plankton and other biomass into a canister within thefunnel's neck. A float scale at the surface displays the dry weight ofthe biomass. (A cubic yard of dry biomass weighs over a ton). It isassumed that a crane or overhead winch will raise and lower thecanisters during harvesting. Nevertheless, smaller boats may not be ableto handle a canister weighing more than 1 ton. They might have toharvest the same funnels several times during their shift. Funnel trapsare designed to withstand hurricanes, but an unattended canister canoverflow with biomass and fill the funnel until it breaks or sinks thearray. Therefore the design includes a “release float” (preferably withno moving parts) that releases any further biomass into the water.

The funnel trap preferably has a main funnel and a bottom funnel. Allinternal surfaces preferably have slick, non-stick surfaces. The mainfunnel is made of strong ultra-light film, such as Mylar™ orpolypropylene. The mouth of the funnel is kept open by any suitablemeans, but in this preferred embodiment the rim is metal and heavierthan water. A debris net attached to the rim keeps large objects fromclogging the funnel. A funnel trap's mouth area of 10,000 ft² isexpected to be standard for oceanic dead zones. Fresh water traps wouldbe much smaller. The trap hangs in the hypoxic zone from 3 or morecables attached to floats. This depth prevents barnacles and insuresthat the plankton are heavy enough to “spin dry.” The light should betoo dim for large shadows to matter, but to be cautious the film shouldbe clear or translucent. Wave action on the floats jiggle the sides ofthe main funnel and help the biomass slide into the canister. A conicalbottom funnel is made of two nested metal funnels that sandwich thebottom of the film and provide needed weight. The removable canisterresides in the neck of the bottom funnel.

When trying to cover some 50,000 square miles it is important tominimize materials. The use of ultra-light thin film is preferred, andthe stress on it should be minimal. This is done in several ways. Theangle that the cone makes with the horizontal depends on the ease of thebiomass' slide. A slicker surface allows a smaller angle requiring lessfilm. A wide mouth on the bottom funnel distributes the weight of thebiomass over a greater area of film. A circular mouth on the main funneluses the least rim material for a given area. Regular polygons(equilateral triangles, squares, etc.) use less rim material thanirregular polygons do. Surprisingly, the area of the film depends onlyon the area of the main funnel's mouth and the angle of the funnel,whether the mouth be circular or a regular polygon.

A loaded canister on deck can be spun dried on its vertical axis tolighten its load. When the centrifuge reaches a certain RPM an apertureat the bottom of the canister starts opening. The biomass, being heavierthan water, is pressed against the cylindrical wall while the water isallowed to drain out the bottom. When the water stops the aperture isclosed and the motor is shut off. To keep the boat itself from spinning,canisters are preferably spun in pairs and in opposite directions. It isanticipated that large service ships or barges will swap empty canistersfor loaded ones and bring them ashore for further processing.

According to a first aspect according to the present invention,apparatus for harvesting biomass (for example plankton, algae,phytoplankton, zooplankton, zooplankton excreta, cyanobacteria, andwhatever else is small enough to get through the debris screen to bedescribed below) includes at least one support float configured to floaton a surface of a body of water. At least one support structure iscoupled to the at least one support float and is configured to support asubstantially rigid frame within a dead zone (for example, a hypoxiczone) below the surface in the body of water. A main funnel is coupledto the at least one support structure within the dead zone, and isconfigured to collect descending biomass and funnel it toward a lowerfunnel that is coupled to the bottom of the main funnel. A collectioncanister is coupled to the lower funnel, and is configured to store thedescending biomass. A guide float is configured to float on the surfaceof the body of water, and a hauling structure is coupled to the guidefloat, and is configured to haul the collection canister from the lowerfunnel to the surface.

According to a second aspect according to the present invention, biomassharvesting apparatus includes a plurality of support floats configuredto float on the surface of a body of water. A plurality of support linesis provided, each being coupled to a respective one of the plurality offloats and configured to extend downward from the surface into a hypoxiczone of the body of water. A rigid frame is coupled to the plurality ofsupport lines, and a main funnel is coupled to the rigid frame andconfigured to catch descending algae. A lower funnel is coupled to abottom of the main funnel, and is configured to guide the algaedescending in the main funnel into a capture device.

According to a third aspect according to the present invention, a methodof harvesting biomass includes the steps of: (i) deploying a pluralityof support floats configured to float on the surface of a body of water;(ii) deploying a plurality of support lines each coupled to a respectiveone of the plurality of floats and extending downward from the surfaceinto a hypoxic zone of the body of water; (iii) deploying a rigid framecoupled to the plurality of support lines; (iv) deploying a main funnelcoupled to the rigid frame; (v) harvesting descending biomass with themain funnel; and (vi) guide the harvested descending biomass with alower funnel coupled to a bottom of the main funnel.

According to a first aspect of alternative embodiments, biomassharvesting apparatus has at least one guide float configured to floatbelow a surface of a body of water. At least one support structure isconfigured to be coupled to a bottom beneath the body of water, and isconfigured to support a substantially rigid frame within a dead zonebelow the surface in the body of water. A main funnel is coupled to (i)the at least one guide float and (ii) the substantially rigid framewithin the dead zone, and is configured to collect descending biomassand funnel it toward a lower funnel that is coupled to the bottom of themain funnel. A collection canister is disposed adjacent the lower funneland configured to store the descending biomass. A hauling structure iscoupled to the guide float, and is configured to haul the collectioncanister from the lower funnel to the surface.

According to a second aspect of alternative embodiments, biomassharvesting apparatus has at least one guide float configured to floatbeneath the surface of a body of water. At least one vertical support iscoupled beneath the at least one guide float and is configured to extenddownward into a dead zone of the body of water. A rigid frame is coupledto the at least one vertical support in the dead zone. A main funnel iscoupled to the rigid frame and is configured to catch descendingbiomass. A lower funnel is coupled to a bottom of the main funnel, andis configured to guide the biomass descending in the main funnel into acapture device. Bottom support structure is affixed to a bottom beneaththe body of water and is configured to support the lower funnel.

According to a third aspect of alternative embodiments, a method ofharvesting biomass includes deploying a guide float configured to floatbelow the surface of a body of water. A support line is coupled belowthe guide float and extends downward into a dead zone of the body ofwater. A rigid frame is coupled to the support line, and a main funnelis coupled to the rigid frame. Biomass descending within the main funnelis thus collected. The descending biomass is guided into a collectiondevice in a lower funnel coupled to a bottom of the main funnel. Thecollection device is hauled to the surface to harvest the biomass.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a funnel trap suspended in a deadzone.

FIG. 2 shows a release float connected to a canister in the bottomfunnel's neck.

FIG. 3 shows an overweight canister that has been released from thefunnel.

FIGS. 4a, 4b, and 4c are top views of three arrays of underwater funneltraps.

FIG. 5 shows how funnel traps in an array can be coupled and uncoupledfrom the surface.

FIG. 6 shows a type-2 canister with its overflow.

FIG. 7a shows a side view of a type-2 bottom funnel, and FIG. 7b shows acutaway of its neck.

FIGS. 8a and 8b show a heavy tripod-anchor with a self-leveling upperplate.

FIG. 9 shows a type-2 bottom funnel attached to the tripod with one ormore springs.

FIGS. 10a and 10b show how a snagging mast attaches to a type-2 canisterand how it holds down the underwater guide float.

FIGS. 11a and 11b depict the type-2 telescoping guide tube and themethod to snag the mast in order to raise the canister.

FIGS. 12a and 12b depict a tool to help deploy and recover type-2 funneltraps.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS

FIG. 1 is a schematic side view of a funnel trap 10 suspended in thehypoxic region 210 of a dead zone, above the anoxic zone 212 and thebottom 214, but below the photic zone 216 and the surface 218. In thispreferred embodiment the top rim 25 that forms the mouth of a mainfunnel 26 should be heavier than water. If the mouth is circular, thetop rim 25 could be a flexible metal rod or band bowed into a circleunder tension. Preferably, three equal-length cables 18 are attached tothree equally-spaced rings 12 along the top rim 25. Each cable 18extends upward, respectively, to three floats 11 that carry the weightof rim 25, ultra-light film 27, and its contents. The funnel 26preferably comprises a film 27, attached to the rim 25, and narrowsconically downward to the bottom funnel 34, where the film is preferablysandwiched between two tightly nested metal cones 261 and 262 (FIG. 2),forming the mouth portion of the bottom funnel 34. The sandwiching ofthe film 27 between the nested metal cones 261 and 262 betterdistributes the weight of the biomass where it is most concentrated.Preferably, the floats 11 transmit wave motion to the top ring 25 viathe cables 18, which helps the biomass slide into the bottom funnel 34.If the top rim 25 is a polygon, three or more cables 18 are attachedequally-spaced to the polygonal rim 25. A horizontal cross section offilm 27 preferably changes smoothly from a polygon into a circle to formthe conical main funnel 26. Preferably, the buoyancy of floats 11 issuch that they are pulled beneath the water in high waves, therebyrelieving the tension on the film 27.

Preferably, a guide float 19 is disposed at the surface 218 and isattached to a vertical guide tube 20 preferably made of nylon netting orother suitable material. The guide float 19 may have lettering or otheridentifier(s) for the harvesting boat that lowers and raises thecanister 36 (FIG. 2). The guide float 19 and the guide tube 20preferably guide the canister 36 into and out of the neck 263 of thebottom funnel 34, and hold the weight of the bottom funnel 34 with threechains 204. Chains are preferably used instead of lines when accuratedistances are required, as their length is relatively constant whenfully extended, and can hold the bottom funnel 34 substantiallyhorizontal. Preferably, the bottom funnel 34 is supported by the guidefloat 19 only. A bottom ring 202 helps to keep the guide tube 20straight. The chains 204 preferably begin at the guide float 19 andattach to the bottom ring 202, from where they extend downward to themouth of the relatively heavy bottom funnel 34. When the chains 204 arefully extended, the film 27 is preferably mildly taut. The film's onlyload is preferably that of the sliding biomass 39, not the bottom funnel34 or its contents, which are preferably supported by the chains 204.The chains 204 preferably do not, however, hold all of the weight of thecanister 36 residing in the neck of the bottom funnel 34. The loadedcanister may weigh several tons, and is preferably supported by a singleline or chain 30 hung from a scale float 16 at the surface. That is, theself-contained scale float 16 and the canister 36 are preferably freefloating and separate from the rest of the funnel structure (except forthe O-rings 362 and 364 to be described below).

Also preferably, a conical debris net 24, made of nylon or othersuitable lightweight yet sturdy material, is affixed to the guide tube20 at connector 22, sloping downward and outward to the top rim 25. Thenet 24 preferably keeps the bottom funnel 34 from being clogged withdebris, and its slope helps to shake off the debris.

FIG. 2 shows the guide float 19, a release float 17, and a canisterapparatus 36 in greater detail. The release float 17 is preferablyattached to a hauling chain 30 that holds the canister 36. The canisterapparatus resides in the funnel trap, but is not attached to it. It isfree floating and preferably adds little or no weight to the trap. Theguide float 19 and its attached chains 204 can easily handle thefrictional forces that the canister apparatus imparts to the 263 neck ofthe bottom funnel 34. The proximity of the guide float 19 and therelease float 17 minimizes the wave differential therebetween. Thatreduces wear on O-rings 362 and 364 by canister 36.

The release float 17 preferably has a rod 15, a hauling ring (or chain)13, and a release stop float 14 on the top of rod 15 that keeps areleased canister from sinking. An adjustable scale stop 152 ispreferably used during initial deployment to adjust the length betweenitself and an empty canister within the neck of bottom funnel 34, asshown in FIG. 2. The float scale 16 is free to move along rod 15 betweenthe float scale stop 152 and the stop washer 154, but in use it ispushed upward by water pressure against scale stop 152. The lower end ofthe rod 15 is preferably connected to a carefully measured chain 30. Theadjustable scale float 16 is preferably scaled to measure the dry weightof the biomass in the canister 36. It also releases the canister when itis full, so that biomass will fall through the bottom funnel and notaccumulate within the main funnel. The depth of the canister can beadjusted from the surface during the initial deployment. The numerals onthe float scale can also be slid up or down and locked in place duringinitial employment.

The canister apparatus preferably includes an upper cage 31 thatattaches the chain 30 to the canister 36, and allows the flow of biomass39 therethrough, while filtering out larger objects and debris which maycome through the guide float, thus avoiding the debris screen. Thehemispherical shape of cage 31 helps canister 36 to be pulled smoothlyupward from its released state below the bottom funnel 34. O-rings 362and 364 keep the bottom funnel's neck relatively free of plankton. TheO-rings can be made of soft substances such as silicone and/orlubricated felt, and/or hard substances such as carbon fiber and/orsplit bamboo. A baffle funnel 35 within the canister 36 keeps mostplankton from drifting upward and out. One or more small holes (notshown) in the upper rim of the baffle funnel 35 vents trapped air andsometimes methane. After the canister 36 is hauled up, it is preferablyplaced upright in a centrifuge and “spun dried” around its verticalaxis. As it reaches a certain RPM, an aperture 37 starts opening torelease water. The lower cage 312 protects aperture 37 and helps lowerfresh canisters into the bottom funnel. Preferably, the canisters 36 canbe spun in pairs and in opposite directions.

As biomass 39 displaces the water in the canister 36, the readings onfloat scale 16 effectively weigh the biomass minus the original weightof the water and the equipment—in other words, the dry weight of thebiomass. The increasing weight lowers release float 17 attached to chain30. By Archimedes' Principle, the upward force of release float 17equals the weight of the water it displaces. The wider the releasefloat's diameter the slower the canister descends as it fills. If acanister is ever allowed to fill to the point where the water level 218reaches the upper rod 15, it preferably drops the canister 36 out of thebottom funnel 34, as shown in FIG. 3. At this point, the stop float 14stops the canister 36 from falling any further. The released canister 36could be capped to keep more weight out, but it is believed thatslightly bobbing waves or a mild current is enough to shake off anyexcess accumulation of biomass. Preferably, the bottom funnel 34 isrelatively heavy, so the friction of the canister's O-rings 362 and 364will not let it get stuck when being raised.

It may happen that the guide float 19 is momentarily in the trough of awave while one or more of the floats 11 are at the peak of the waves.Thus, large waves could put tremendous stress on film 27 and tear it.Therefore, the buoyancy of floats 11 are preferably pre-calibrated to bepulled underwater when under too much stress. Then, the film 27 becomestaut but not enough to cause damage. Thus, a lighter film can be used.

FIG. 3 shows the canister 36 in its released state. The canister hasdropped far enough below bottom funnel 34 to avoid it accumulatingsignificant further amounts biomass.

With an invention potentially covering a huge part of our planet, thecardinal rule is “First, do no harm.” FIGS. 4a, 4b, and 4c addresses apotential ecological problem. Notice that these huge funnels and theirconnectors form a horizontal underwater net. If a migratory school offish, marine mammals or another life forms happen to wander into thedead zone under the net, they may become disoriented and try to escape,perhaps in all directions. Dead zone floors are littered with carcasses.Some may be guided upward by the funnel toward the oxygen rich photiczone and escape, but some may be trapped under it because the spacebetween funnels may be too small. Marine mammals don't breathe dissolvedoxygen and, though their eyes might burn from the water acidity, theyshould know how to come up for air. If they happen to get lost under thearray looking for an opening large enough, they may suffer cruel deaths.Endangered blue whales are said to grow 100 feet long or longer, no oneknows for sure, and they should have a wide turning radius. Two simplerules preferably should be followed:

-   1. Connect polygonal mouthed funnels only at their corners, as in    the checkerboard pattern of array 42 in FIG. 4b . If any were joined    along adjacent sides, an animal swimming upward to where the sides    join might not know which way to turn and die of asphyxiation.-   2. In a body of water, each funnel should have a space around it    that can accommodate the largest creature in that body of water. In    an oceanic dead zone, distances 41, 43 and 45 in FIGS. 4a, 4b, and    4c should be a hundred feet or more. In fresh water they might be    ten to thirty feet.

FIGS. 4a, 4b, and 4c are top views of three arrays designed forunderwater funnel traps 10 held in place by one or more anchored buoys(not shown). The funnels are connected by their underwater top rims 25.Array 40 preferably includes round-mouth funnel traps connected bycables equal to the diameter of the funnels giving 25.3% coverage. Array42 preferably comprises square mouth funnel traps in a checker boardpattern giving 50% coverage. Array 44 preferably includes round mouthfunnels with the horizontal and vertical openings between them the sizeif their diameters, giving 58.9% coverage.

FIG. 5 shows one way for boats at the surface to couple and uncouplefunnel traps 10. It is preferred that each trap can move vertically inthe waves independent of one another. Deploying traps and removing themare preferably done only at the start and end of a dead zone season.Preferably, two strong upright connector tubes 50 are rigidly attachedto top rims 25 of adjoining funnel. Openable shackles 52 are preferablyattached to each other with a rod or a chain 321. As depicted in FIG. 5,they fit loosely around connector tubes 50 and conjoin two or morefunnel traps. Cords 54 emanating from within the connector tubes and areattached to floats 56 at the surface 218. Another cord 55, preferablytied to the rod (or chain) 321 conjoining shackles 52, is attached tofloat 57 at the surface 218. These cords are preferably left slack toreduce wear on the tubes 50 and the cords themselves. To decouple thefunnel traps, the cord 55 is hauled up, the shackles 52 are opened, andthey are removed from the cords 54. To couple the funnel traps again,bring them together by slowly pulling cords 54 from their floats 56,close the shackles around cords 54, and let them slide down onto theconnector tubes.

It is conservatively expected that a funnel with a mouth area of 10,000ft² will capture more than one dry ton of biomass/day. If a work boatharvests a canister every 20 minutes they will harvest over 24tons/8-hour shift. It is also expected that the biomass will containabout 25% carbon, which can produce about 6 tons of methane and perhaps18 tons of fertilizer/8-hour shift. Of course the boat may opt to run 3shifts per day. The biomass should be desalinated if it is to be sold asfertilizer.

In alternative embodiments if FIGS. 6-12, so-called “type-2” funneltraps preferably have no floats on the surface, except when activelyharvesting. Preferably, the main funnel 26 in FIG. 1 is unchanged exceptfor the bottom funnel 34. Type-2 funnel traps are preferably notconnected to one another. Instead, they are preferably anchored onheavy, self-leveling tripods at the bottom of the lake or ocean. Withoutsurface floats, these embodiments do not use wave action to help slidethe biomass down the main funnel into the canister, but another kind of“shake down” is provided below in the description of FIG. 9.

FIG. 6 depicts a type-2 canister 60. Hauling ring 601 attaches line 30(see FIG. 10) to an underwater guide float 19 above it. Line 30 issufficiently strong to raise a canister full of biomass 60. Cage 602allows the falling biomass to pass through into cylindrical tube 612.The streamlined shape of cage 602 allows it to be pulled through guidetube 720 smoothly without damaging the material. Cage 602 is affixed tothe canister's strong upper rim 604, which, in turn, is attached tocylinder 612 and to internal baffle funnel 606 at join 605. Items601-607 may be removed for maintenance preferably by unscrewing join605. Join 605 should have one or more very small vent holes to releaseany air trapped between baffle funnel 606 and cylinder 612. A gasket(not shown) is affixed to the bottom of rim 604 to seal the conical seat628 in bottom funnel 7 a (in FIG. 7a ). The diameter of the bafflefunnel's vent 607 should be larger than the largest hole in the debrisnet to keep it from clogging. The biomass overflow release system isshown in 608-611. A truncated cone with open top 608 and an open bottom609 that is attached to cylinder 612. There is no egress below open top608, except through 608 itself. Since biomass is substantially heavierthan water it will gradually displace the water and become compactedfrom the bottom of cylinder 612 upward. As it reaches the “full” level,608, more and more dead plankton, etc., will escape to the outside of608, fall through an escape hatch 610 and out of canister 60 as shown in611. The simplicity of having no moving parts is worth more than thesmall amount biomass that may be lost during normal collection. Cylinder612 is weighted at its bottom 614 for greater stability and speed oflowering when empty. Weighted bottom 614 can be removed via nut 616along with cage 618 for emptying and cleaning.

FIG. 7a shows a cutaway of a bottom funnel, and FIG. 7b shows a sideview of its open neck 646. Referring to FIG. 1 the bottom of the thinfilm 27 that forms the sides of the main funnel 26 is preferablysandwiched between two cones 624 and 626. That spreads and reduces theforces on thin film 27 as the canister gets heavier. Upper rims of 624and 626 are preferably rounded 629 to keep them from cutting the film.Three or more equal-spaced hooks 623 are preferably used to hold downbottom ring 202 as shown in FIG. 1. The lowest conical area 628 justabove cylindrical neck 632 preferably houses the upper rim 604 of thecanister 60. The reinforcement ring/neck 634 is preferably used toattach rods 644 that make up bottom funnel's neck 70 b, and tostrengthen it enough to deploy when the dead zone begins and to removewhen the dead zone ends (see FIG. 12). The open cage formed by rods 644allows biomass overflow to escape the neck 70 b. The deliberately heavybase 649 and flange 648 help to hold the main funnel rim 25 horizontal.Base 649 is filled with concrete and/or metal to keep the base stable.

FIGS. 8a and 8b depict a tripod-anchor with a self-leveling upper plate.The main function of the tripod-anchor is to hold the funnel trap inplace at the bottom so that the harvesting boat can locate theirassigned traps, preferably with a GPS, and to deploy and recover thetraps themselves. The feet 662 can be added, removed, or modified (e.g.,with spikes) as appropriate for the bottom conditions. The legs 666 ofthe tripod 66 are strong, heavy rods attached to plate 672, which platepreferably houses a central ball joint 674. The leveling mechanismcomprises a heavy weight 668 held by rod 670 that pierces the ball joint674 and continues upward and is rigidly attached to plate 676. Noticethat plate 676 is substantially horizontal despite irregular heights ofthe feet as shown in 80 b. The flange 648 and/or the base 649 may becoupled to the plate 676.

In FIG. 9, the bottom funnel 70 b is preferably attached to the tripodanchor 666. The bottom funnel's weighted flange 648 is preferablyattached to and seated upon a biasing structure, e.g., compressionspring 680, which is preferably mounted atop of and attached to plate a676. The flange 648 and the plate 676 are preferably connected with twoor more spacer bolts 678, as shown. Under enough force, the flange 648can move downward as far as the compression spring 680 will allow,limited by the non-threaded portion 675 of the bolts 678 and the nuts679.

With the arrangement of FIG. 9, a harvester (e.g., boat/ship) canperiodically raise the canister 60 and then drop it back onto spring 680to produce vibration/shock/force waves in film 27 that can help biomass391 (FIG. 1) slide down the sides 27 of main funnel 26. Spacer bolts 678also serve as a safety feature that keeps the bottom funnel 70 b andtripod anchor 666 connected if the spring 680 breaks loose.

FIGS. 10a and 10b show a type-2 harvesting apparatus 100, including asnagging mast (702-710) preferably attached to an underwater guide float19, a guide tube 720, and the canister 60. The weight of an emptycanister 60 should be more than the net upward buoyancy of everythingabove it: i.e., the float 702, the snagging mast 706, the hold-down disk708, and the guide float 19, so that the canister 60 is not pulled upuntil it needs to be. In this preferred embodiment, four carabiners 704are preferably rigidly attached to a smooth light-weight mast 706. Sincethe funnel trap is preferably delivered in kit form, the mast 706 shouldbe seamlessly joined together from shorter pieces. Any one of carabiners704 should be able to hold a full canister 60. The hold-down disk 708 ispreferably rigidly affixed to the bottom of the mast 706, with a line 30extending from a connector 710 coupled to the bottom of the plate 708.Connectors 710 are preferably used to couple to the guide float 19. Line30 preferably has a length that holds the guide float 19 down so that afloat 702 is at a desired depth (perhaps 65′ more or less) for captureby the harvester. When the canister 60 is being raised and the carabiner710 reaches the surface, it is preferably removed from the bottom of thehold-down disk 708 and is re-attached to a line on the hauling winchthat continues to raise canister 60 through the telescoping guide tube720 and the guide float 19, both now at the surface. Guide tube 720 ispreferably covered by a strong thin material 722 that stretchessomewhat, e.g. nylon stocking material.

FIGS. 11a and 11b show a method to snag the mast 708, and to raise andlower the canister 60. One or more harvesting boats 750 pull a lineattached to outrigger booms 751. Weights 754 form a U-shape in the line.The bottom of the U is a line 752 that should be between depths 748 and749 (e.g., depth 748 may be from about 20 feet to about 200 feet; depth749 may be from about 25 feet to about 225 feet). It is important thatbottom line 752 should be above the guide float 19. As the boat 751moves forward, the line 752 catches the mast 708 bending it forward anddownward so that horizontal line 752 slides up the mast 708 and cannotescape and is trapped by snagging one or more of the carabiners 706. Theharvesting boat 751 then hauls up the retrieval mechanism shown in FIG.11a . The guide tube 720 is preferably made slack enough to stretch tothe surface even during the highest tides and moderate waves. Harvestingshould not be performed when storm waves are too high to have the line752 to remain between depths 748 and 749. When the connection betweenthe bottom of the mast 708 and the guide float 19 reaches the surface,the mast 708 is preferably unhooked and the harvesters preferablyre-hook the upper end of the line 30 and haul up the canister 60. Atthis point, the guide float 19 preferably remains on the surface by itsown buoyancy, stretching out the guide tube 720 to receive the same oranother empty canister.

The above-described process may be reversed by re-attaching emptycanister 60 to the bottom of the line 30 and lowering it into the guidetube 720 until the upper end of the line 30 reaches the guide float.Then, the carabiners 706 are re-attached to the mast 708 and guide float19. The canister will then pull both of these down into place.

The best time to deploy a trap accurately is at slack tide on a calmday. One way to deploy the trap may be visualized in FIGS. 12a and 12b ,which comprise a side view of a specialized tool 120 a and an insideview 120 b that helps to deploy a type-2 trap in a dead zone and removeit after the dead zone season is over. Referring to the funnel trap inFIG. 1 it is clear that the easiest way to lower and raise the funneltrap is to go through the guide float 19, the telescoping guide tube720, and then into the bottom funnel 70 b (FIG. 11b ). Ring 802 is anattachment ring for a line to lower and raise a type-2 funnel trap. Asmooth outer shell 804 allows the tool 120 to take that route withouttearing the material 722.

Referring to FIG. 11b , when removing a type-2 funnel trap the canistershould first be retrieved and guide float 19 will still be at thesurface. Then with arms 810 outspread as shown in FIG. 12b lower tool120 as far as it can go, which would be bottom 649 of bottom funnel 7 b.When raising tool 120 the outspread arms will hook under reinforced ring634 (FIG. 7) and the entire funnel trap can be lifted on deck where itcan be disassembled. For deploying or moving, tool 120 is again hookedunder reinforced ring, but after it is placed tool 120 is lowered untilarms latch inside the shell. The smooth outer shell 804 has no sharppoints or edges that could tear the material 722 in the guide tube 720.Affixed to the inside of shell 804 are opposing bushings 811 that holdthe ends of an axle 808 so that the arms 810 are aligned with atwo-pronged fork 812. If not thus-constrained, the arms 810 will fallopen by gravity; but, when they are being lowered through the guide tube720 or the bottom funnel neck 632, the arms 810 are easily pushed upalong path 806. The arms 810 preferably have a rectangular cross sectionthat is rounded wherever it can rub against anything outside of shell804, to keep the guide tube material 722 unharmed. The open bottom 815of the shell 804 is preferably rolled inward for the same reason.

Near the bottom of the shell 804 is a strong horizontal disk 814preferably affixed to shell 804 with machine screws. One or more holes816 allow water to move freely there through. At the center of disk 814is a preferably square hole that keeps the handle 812H of thetwo-pronged fork 812 from turning. It should be in the same plane as thearms 810, and 812 should only move vertically. If the bottom of theflat, two-pronged fork is pushed up through the square hole (obscured)in disk 814, it will raise the arms 810 along the path 806 until thearms 810 are pushed through the slots 828. If the tool 120 a is loweredto the base 649 of the bottom funnel 70 b, a “door latch” 818 will bepushed through the square hole and lock the arms inside the shell 804.This allows the tool 80 to be raised after the type-2 trap is deployed.A simple switch under the shell 806 resets the latch 818. Removing atype-2 funnel trap is a reversed process, but that simple switch is usedto completely disable latch 818.

The individual components shown in outline or designated by blocks inthe attached Drawings are all well-known in the plankton harvestingarts, and their specific construction and operation are not critical tothe operation or best mode for carrying out the invention.

While the present invention has been described with respect to what ispresently considered to be the preferred embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments. To the contrary, the invention is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. The scope of the following claims is to beaccorded the broadest interpretation so as to encompass all suchmodifications and equivalent structures and functions.

What is claimed is:
 1. Biomass harvesting apparatus, comprising: atleast one guide float adapted to float below a top surface of a body ofwater; at least one support structure adapted to be coupled to a body ofwater bottom beneath the body of water, and adapted to support a rigidframe within a dead zone below an oxygenated photic zone below the topsurface in the body of water; a main funnel coupled to (i) the at leastone guide float and (ii) the rigid frame within the dead zone, andadapted to collect descending biomass and funnel it toward a lowerfunnel that is coupled to the bottom of the main funnel; a collectioncanister is disposed adjacent the lower funnel and adapted to store thedescending biomass; and hauling structure coupled to the guide float andadapted to haul the collection canister from the lower funnel to thesurface through the neck of the lower funnel.
 2. The apparatus accordingto claim 1, further comprising a guide tube coupled to the guide floatand to the lower funnel, and adapted to guide the canister as it ishauled to the surface.
 3. The apparatus according to claim 2, furthercomprising at least one debris shield coupled to the rigid frame andadapted to divert debris from entering the main funnel.
 4. The apparatusaccording to claim 1, wherein the at least one support structure has asupport plate structure at a top thereof and which is adapted to supporta bottom of the lower funnel.
 5. The apparatus according to claim 1,wherein the canister has at least one diverter window to divert biomassfrom the canister.
 6. The apparatus according to claim 1, wherein themain funnel comprises a flexible lightweight sheet material.
 7. Theapparatus according to claim 1, wherein the at least one supportstructure includes a weight adapted to hold the at least one supportstructure to the body of water bottom beneath the body of water. 8.Biomass harvesting apparatus, comprising: at least one guide floatadapted to float below a top surface of a body of water; at least onesupport structure adapted to be coupled to a body of water bottombeneath the body of water, and adapted to support a rigid frame within adead zone below an oxygenated photic zone below the top surface in thebody of water; a main funnel coupled to (i) the at least one guide floatand (ii) the rigid frame within the dead zone, and adapted to collectdescending biomass and funnel it toward a lower funnel that is coupledto the bottom of the main funnel; a collection canister is disposedadjacent the lower funnel and adapted to store the descending biomass;and hauling structure coupled to the guide float and adapted to haul thecollection canister from the lower funnel, wherein the support platestructure has a ball joint structure adapted to keep the bottom of thelower funnel horizontal.
 9. The apparatus according to claim 8, furthercomprising biasing structure adapted to impart vibrations to the mainfunnel.
 10. Biomass harvesting apparatus, comprising: at least one guidefloat adapted to float beneath the top surface of a body of water; atleast one vertical support coupled beneath the at least one guide floatand adapted to extend downward into a dead zone below an oxygenatedphotic zone below the top surface of the body of water; a rigid framecoupled to the at least one vertical support in the dead zone; a mainfunnel coupled to the rigid frame in the dead zone and adapted to catchdescending biomass; a lower funnel coupled to a bottom of the mainfunnel, and adapted to guide the biomass descending in the main funnelinto a capture device; bottom support structure affixed to a body ofwater bottom beneath the body of water and adapted to support the lowerfunnel; and hauling structure coupled to the at least one guide floatand adapted to haul a collection canister from the lower funnel to thesurface through the neck of the lower funnel.
 11. The apparatusaccording to claim 10, wherein the main funnel comprises a flexiblelightweight sheet material shaped as a funnel with a top open endoriented toward the surface.
 12. The apparatus according to claim 10,wherein the rigid frame is adapted to be vibrated by raising andlowering the at least one vertical support.
 13. The apparatus accordingto claim 10, wherein the rigid frame comprises a circular shape.
 14. Theapparatus according to claim 10, further comprising: a hold-down discadapted to hold the guide float below the surface; and a guide tubecoupled to the guide float and adapted to guide the capture device fromthe lower funnel to the guide float.
 15. The apparatus according toclaim 14, further comprising a debris shield coupled to the rigidstructure and to the guide tube.
 16. The apparatus according to claim14, wherein the collection canister has at least one diverter window todivert the biomass from the collection canister.
 17. The apparatusaccording to claim 10, further comprising a plurality of connectorscoupled to the at least one guide float, and adapted to captured by avessel disposed on the surface of the body of water.
 18. Biomassharvesting apparatus, comprising: at least one guide float adapted tofloat beneath the top surface of a body of water; at least one verticalsupport coupled beneath the at least one guide float and adapted toextend downward into a dead zone below an oxygenated photic zone belowthe top surface of the body of water; a rigid frame coupled to the atleast one vertical support in the dead zone; a main funnel coupled tothe rigid frame in the dead zone and adapted to catch descendingbiomass; a lower funnel coupled to a bottom of the main funnel, andadapted to guide the biomass descending in the main funnel into acapture device; bottom support structure affixed to a body of waterbottom beneath the body of water and adapted to support the lowerfunnel; and hauling structure coupled to the at least one guide floatand adapted to haul a collection canister from the lower funnel to thesurface, wherein the bottom support structure comprises a tripod havinga horizontal plate structure at a top thereof.
 19. The apparatusaccording to claim 18, wherein the horizontal plate structure includes aleveling structure adapted to support the bottom support structure in ahorizontal position.
 20. A method of harvesting biomass, comprising:deploying a guide float adapted to float below the top surface of a bodyof water; deploying a support line coupled below the guide float andextending downward into a dead zone below an oxygenated photic zonebelow the top surface of the body of water; deploying a rigid framecoupled to the support line; deploying a main funnel coupled to therigid frame in the dead zone; harvesting descending biomass with themain funnel; guiding the descending biomass into a collection device ina lower funnel coupled to a bottom of the main funnel; and hauling thecollection device to the surface to harvest the biomass through the neckof the lower funnel.